The Collaborative International Dictionary of English v.0.48:

Arianize \A"ri*an*ize\, v. i.
   To admit or accept the tenets of the Arians; to become an
   Arian.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Arianize \A"ri*an*ize\, v. t.
   To convert to Arianism.
   [1913 Webster]